It is used to help in the determination of the Karl Pearson’s coefficient of correlation ‘ r ’. Due to this ‘ r ’ is corrected to a great extent but note that ‘ r ’ depends on the random sampling and its conditions. it is given by
P. E. = 0.6745
If the value of r is less than P. E., then there is no evidence of correlation i.e. r is not significant.
If r is more than 6 times the P. E. ‘ r ’ is practically certain .i.e. significant.
By adding or subtracting P. E. to ‘ r ’ , we get the upper and Lower limits within
which ‘ r ’ of the population can be expected to lie.
Symbolically e = r ±
P = Correlation ( coefficient ) of the population.
Example If r = 0.6 and n = 64 find out the probable
error of the coefficient of correlation.